I have a 2013 which I bought in nov 2012. I live in Georgia and get virtually no snow. On several occasions when driving to work on rainy days, my windshield will fog up half of the windshield and much of the front door windows. No matter what I do, the fog will not go away, no matter what setting I use. I took it to the dealer and they said they had no idea what it was.
Wish there was something I could do.
There is but it would be nice if VW would test this stuff and fix it themselves. In heavy rain, you use defrost, windows start fogging so you turn the fan on high.... should be good, right? heh. wrong. What happens is the airflow into the HVAC system exceeds what can sneak under the cowl cover, creating a negative pressure under the cowl. This pulls mist off wheels into the cowl area, which makes it's way into the hvac system. The same thing that happens in snow happens in rain, it's just less of a PITA. You can verify this by pulling out the pollen filter after driving in heavy rain, it will be wet. It's just a dumb design, made worse by trying to fix the snow problem.
The fix is to allow high pressure air from the cowl/windshield area to get to the hvac intake. My car is currently at the dealership where they are attempting to rectify this, if that doesn't prove fruitful, which I doubt it will as they are limited in what they can do, I'm going to install frogskin vents in the cowl. They are basically a fine plastic screen we use on snowmobiles to let cooling air in , and keep snow out of the hood. THey are available in 2" round and 3X4" rectangular panels. I figure a few of these on the cowl should allow enough air in to balance off the hvac requirements and prevent sucking snow and dust off the road through the drains.
It was just so much simpler with the pollen filter on top of the hvac intake, pity they screwed this up. Anyone know if an earlier passat or jetta hvac intake pollen filter holder will fit the newest passat hvac intake? This worked on A3 and 4 golfs to allow pollen filters on cars that never had them....